Solution:
The divisor of 7 14 is 2,3, 119,6,357,1.
That unit number can't be 1, 2, 3, 6, because 7 and 4 are already used.
So one digit is five.
And the numbers 2, 3, 6, so 3 is the tail, 623, 263 will do.
2. A: 29, 92, 38, 74, 56, 65.
Answer: Let this composite number be—
xy .
Then it is (10x+y)+(10y+x) = n 2.
1 1(x+y)=n^2
When x+y= 1 1,
Then the answers are 29, 92, 38, 83 (except prime numbers), 47 (except prime numbers), 74, 56, 65.
Answer: Welcome+Spring+Cup+Good =2+3+7+9=2 1.
Solution: let English be x, spring y be a and cup a be B.
Then it is (10x+a) (10y+a) =11b.
Square 1, 2, 3, 4, 5, 6, 7, 8, 9, 0.
Get:
One digit after the number is squared.
1 1
2 4
3 9
4 6
5 5
6 6
7 9
8 4
9 1
0 0
Then select 999 as the object.
Guess 27*37=999.
Welcome+Spring+Cup+Good =2+3+7+9=2 1
4. Is the topic wrong?
5. Where's the map?
6. The total number of sixth-grade students can be divisible by 5, and the single digit must be 5.
The number of boys is divisible by 3.
It is inferred that the total number of sixth-grade students is 435.
Boys 2 16.
7. The number of "hope" is 0.
These two natural numbers are 165 and 56 1.
From 102*20 1=20502.
203*302=6 1306
123*32 1=39483
The product of the reverse order of two natural numbers is 92565, which can be deduced as 165*56 1=92565.